Hurth ZF 45a

[scenarioL113]

Anyone running a hurth zf45a or hsw450a (same unit)?

The bottom bolt hole on each side is not capable of accepting a bolt. The "boss" casting of the transmission case does not have enough room to get a bolt in the hole.

I put a stud on the 2 bottom bolt holes on the adapter plate. I then put a nut after the trans was in place. I must say they did not give much room at all for those 2 bottom bolts. The pattern is the typical borg warner 6 bolt style.

I lok-tited them in place and then lok-tited the nuts as well. I think they will be ok.

Has anyone else had to deal with this problem. I am not sure if the zf63a suffers a similar problem or not.

These are mated up to cummins 4bt 150hp in my B28. Looks like even with the 8 degree down angle that there will be slight interference with the hatch covers.

I will need to put in a lot of figuring time before I order new shafts. It is hard to determine new shaft length to meet the trans coupler.

there seems to be a number of variables that come in to play to get it right.

How far from the hull would it be a safe distance for the transmission casing to sit? Would it be OK to have a half inch clearance?

[CaptPatrick]

How far from the hull would it be a safe distance for the transmission casing to sit? Would it be OK to have a half inch clearance?

That particular spot of the hull is captured on either side by the engine beds and aft by whatever bulkhead there is in the B28, so it's a pretty stiff area in terms of hull flexing.

You do have a remarkable amount engine movement from torq and movement fore and aft to some degree between forward running and backing down.

All of these movements should be well under 1/2", but I'd certainly keep the 1/2" clearance as dead minimum. Remember also that when you do your final engine alignment you just might have to make an adjustment down at the back of the engine which could kill your 1/2" clearance sitting on the hill.

Br,

Patrick

[Bruce]

The Hurth series of gears uses studs and nuts on the lowest point for securing to the flywheel housing plate. That is normal.

I would not use loctite on the nuts. A lock washer or lock nut is fine. It makes removal of the gear in the boat very difficult.

It is hard to determine new shaft length to meet the trans coupler.

Once engine is in place where its going to sit, measure from the tranny coupling face to the back of the strut cutlass.

Add the appropriate distance for the shaft diameter spacing, probably 3/4 to 1" and then give that distance to the shaft maker and tell them to add the taper to that.

If your struts are not up yet, then go ahead and mount them.

[scenarioL113]

Thanks guys. That is what I figured but I sometimes the obvious is not the case.
I already lok-tited the 2 lower ones but not the others. I will not do that on the other gear though.